1. Field of the Invention
The present invention relates to an air cleaning system, and more particularly to an air cleaning system having a forced negative pressure generating function which may be installed in a room or the like for forming an air curtain to define a predetermined space in part of the room, such that the predetermined area may be utilized as a smoking area or the like to prevent malodorous and harmful smoke from diffusing out of the predetermined space.
2. Description of the Related Art
Conventionally, partitions have been often used to surround part of a room to utilize the space defined by the partition walls as a smoking area or a tea drinking area. The partitions, however, are intended to surround a space within a relatively large room, so that air may freely come in and out the surrounded space through open areas between the upper edges of the partitions and the ceiling or between the lower edges of the partitions and the floor. Thus, contaminated air (smoke, exhaust gas, harmful gas) and bad smell possibly produced in the surrounded space may flow out to cause the contamination in the entire room.
For preventing this inconvenience, a partition having a built-in air curtain producing system, as illustrated in FIGS. 1 and 2 has been proposed. Specifically explaining, the illustrated partition a has a built-in air fan b, an air blow-out port c on the top for forming an air curtain, and an air suction port d on a lower side portion. Several units of the partitions a are placed in combination on a floor h to surround a portion of a room with their suction ports d directed to the inside of the surrounded space. A suction fan f is also installed in the ceiling e above the portion of the room surrounded by the partitions a. The air fans b are operated to blow air from the blow-out ports c to form air curtains q such that a predetermined space i is surrounded together with the floor h, ceiling e, and partitions a. Then, air within the predetermined space i is exhausted by the suction fans f out of the space i to produce a negative pressure therein, such that contaminated air, bad smell and so on possibly produced within the space i are prevented from diffusing throughout the room.
However, even if the prior art air curtain producing system allows a portion of a room to be simply surrounded by the partitions a for use as a smoking area or a tea drinking area, the suction fan f, the installation of a duct for exhausting contaminated air and bad smell, and an associated piping system are required in the ceiling e and other external places. Thus, available places are limited, and the entire system cannot be readily installed in any desired place.
Further, since the predetermined space i surrounded by the air curtains a must be always maintained at a negative pressure in order to prevent contaminated air and bad smell in the predetermined space i from flowing therefrom, the suction fan f must exhaust an amount of air larger than the amount of air involved by the air curtain q from the outside of the predetermined space i. Such a large amount of exhaust air would adversely affect air conditioning facilities of the entire building.
To solve the above-mentioned problem, the present inventor has proposed a screen having an air cleaning function, as illustrated in FIG. 3, in U.S. Pat. No. 5,264,015. In a predetermined space i surrounded by the screens, the air flow amount sucked by a fan f is larger than an air amount externally involved by an air curtain q from the outside of the space i, thus maintaining a negative pressure within the space i, and air sucked by the fan f is cleaned by a built-in air cleaner and discharged to the outside. This screen having an air cleaning function advantageously surrounds part of a room for readily providing a place serving as a smoking area or a tea drinking area without exerting any influence on an air conditioning facility of the room such as cooling, heating, and so on. However, since a plurality of screens are installed in a room, the entire layout of the room must be taken into consideration. Also, since the screens define a place together with part of the ceiling and part of the floor of a room, the screens cannot be effectively utilized in a room having a high ceiling. In addition, the screens, when installed in a room, will obstruct the view in the room.